Preserving the Hearing Health of Military Service Members

Military audiology has achieved cutting-edge research advances, including boothless audiometry for detecting hearing loss in soldiers who are still on the battlefield, new protective devices that prevent noise-related hearing loss while preserving soldiers’ situational awareness and safety, and animal models that are uncovering the mechanisms behind blast injuries.

These impressive research efforts are often done in conjunction with daily, more prosaic but no less important tasks, such as helping fit service members with hearing aids and treating them for the debilitating effects of tinnitus.

Isaac D. Erbele, MD, a lieutenant colonel in the U.S. Army and a neurotologist at Brooke Army Medical Center (BAMC) in San Antonio, Texas, embodies this bench-to-bedside approach. “I have a busy case load both at BAMC and at the South Texas VA,” Dr. Erbele said. “I go back and forth between active duty and veteran populations,” focusing on conditions typical of military personnel, including noise-induced hearing loss and tinnitus. But research is also a keen interest for him.

“I am doing everything from bench studies all the way up to clinical trials, because I pride myself in being a truly translational researcher,” Dr. Erbele said. Many of those research projects are done, he added, via his connections with the Department of Defense (DOD) Hearing Center of Excellence, in San Antonio, and the Uniformed Services University of the Health Sciences, in Bethesda, Md.

One area Dr. Erbele is most excited about involves the use of otic organoids, which are laboratory-grown, three-dimensional structures derived from stem cells that model the inner ear. “Basically, we’re trying to take human pluripotent cells to approximate cochlear hair cells and determine what kind of mechanisms occur with blast trauma to see if there are opportunities for therapeutic interventions,” he explained. “That’s been a little slow-going, but I’m hopeful that we get some publications out soon.” (For more details on otic organoid research, see a recent review coauthored by Dr. Erbele: Bioengineering (Basel). doi: 10.3390/bioengineering11050425).

“We are also doing several blast studies in rats and sheep where we introduce at least temporary, if not permanent, hearing loss threshold shifts and then test several therapeutics to improve the animal’s hearing after their noise trauma,” he said. “So far, we’ve looked at anti-inflammatory agents and have seen some very encouraging results.”

Dr. Erbele is also working on a nerve regeneration therapeutic model in larger animals, “which is great because it affords a closer approximation of the human cochlea and hearing. So, there’s an opportunity for more translational work as well, which we are very excited about.”